• Title/Summary/Keyword: component mode synthesis

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Hybrid Component Mode Synthesis Considering Residual Dynamic Flexibility Attachment Mode (잔여 동연성 부가 모드를 고려한 혼합 부분 모드 합성법)

  • Cha Hyun Joo;Kim Jin Ho;Lee Shi Bok
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.29 no.5 s.236
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    • pp.716-725
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    • 2005
  • The method of substructure synthesis o. component mode synthesis(CMS) provides an effective means of dynamic analysis of very large and/or complex structures. In this study, residual dynamic flexibility attachment modes in hybrid component mode synthesis are considered for the purpose of exactly compensating the effect of higher order truncated modes. Following this way, the analysis accuracy of the synthesized structure can be improved effectively with less computational effort. In order to show the accuracy and effectiveness of the proposed hybrid component mode synthesis(HCMS), numerical experiments were carried out for the models of a clamped-clamped beam. The results verified the effectiveness of the proposed method.

Improved component mode synthesis method using experimental obtained modal data (실험모달데이터를 사용한 구분모두 합성법의 개선)

  • 장경진;지태한;박영필
    • Journal of KSNVE
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    • v.6 no.1
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    • pp.97-106
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    • 1996
  • This paper presents systematic study of the experimental application of a free-interfaced component mode synthesis method. In the free-interfaced component mode synthesis method, an error the to truncated higher modes and neglected ineria loadings on a component from the connected component is inherent. Also, it is difficult to directly use experimental modal data in a modal synthesis method which links experimental model to finite-element model because of many inconsistencies between experimentally obtained and analytically obtained modal vectors and missing degrees-of-freedom (DOFs) such as rotational DOFs. In order to solve these problems, three methods, the first one based on attaching auxiliary weights to the connection points, the second one utillizing the normalization of experimental modal vector, and the third one generating smoothed and expanded experimental mode shapes, are studied in this paper. Finally, the study is illustrated for a flat-plate structure by using simulated and measured experimental data.

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Substructure Synthesis Method using Dynamic Reduction (동축소법을 이용한 부분구조합성법)

  • 박석주;박성현;김성우
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.1
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    • pp.82-87
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    • 2000
  • The component mode synthesis method(CMS) used for vibration analysis has demerit that error becomes larger, as degree of natural frequency grows higher. The reason of error occurrence is that Guyan's static reduction is used and the number of modes taken in each component is deficient. This paper proposes the substructure synthesis method using dynamic reduction to solve the problem from the component mode synthesis method. Computer simulation for the proposed method. FEM and the component mode synthesis method(CMS) on a rectrangular plate has been carried out to prove the avilability of the proposed method.

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Structural Dynamics Modification of Structures Having Non-Conforming Nodes Using Component Mode Synthesis and Evolution Strategies Optimization Technique (부분 구조 모드 합성법 및 유전 전략 최적화 기법을 이용한 비부합 절점을 가진 구조물의 구조변경)

  • 이준호;정의일;박윤식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2002.05a
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    • pp.651-659
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    • 2002
  • Component Mode Synthesis (CMS) is a dynamic substructuring technique to get an approximate eigensolutions of large degree-of-freedom structures divisible into several components. But, In practice. most of large structures are modeled by different teams of engineers. and their respective finite element models often require different mesh resolutions. As a result, the finite element substructure models can be non-conforming and/or incompatible. In this work, A hybrid version of component mode synthesis using a localized lagrange multiplier to treat the non-conforming mesh problem was derived. Evolution Strategies (ESs) is a stochastic numerical optimization technique and has shown a robust performance for solving deterministic problems. An ESs conducts its search by processing a population of solutions for an optimization problem based on principles from natural evolution. An optimization example for raising the first natural frequency of a plate structure using beam stiffeners was presented using hybrid component mode synthesis and robust evolution strategies (RES) optimization technique. In the example. the design variables are the positions and lengths of beam stiffeners.

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Modal Analysis of Steel Box Bridge by Using the Component Mode Synthesis (CMS 방법에 의한 강교량의 동적모드해석)

  • 조병완;박종칠;김영진
    • Proceedings of the Computational Structural Engineering Institute Conference
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    • 1997.04a
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    • pp.177-184
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    • 1997
  • The Component Mode Synthesis Method for the -vibration analysis can be applied to the large-scaled structures, which have difficulty in modeling because of their intricate shapes and boundary conditions and need much time in computational calculations. This paper uses the Component Mode Synthesis Method to analyze the free vibration for the steel box bridge having the large number of D.O.F as an example of the large structural system. By comparing the CMS method to the other method (FEM), this paper proves the accuracy of the solution in techniques and the efficiency in time.

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Modal Analysis of Plate by Substructure Synthesis Method (부분구조합성법을 이용한 판의 모우드해석)

  • Jung, Jae-Hoon;Jee, Tae-Han;Park, Young-Pil
    • Journal of the Korean Society for Precision Engineering
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    • v.11 no.6
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    • pp.65-74
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    • 1994
  • Various substructure synthesis methods, such as component mode synthesis, building block analysis and reduced impedance method, are studied for the determination of vibration characteristics of plate problems. Comparisons are made for each methods in terms of accuracy and computational efficiency. Following conclusions are made from the results of computer simulations and experiments. i) The computation time of component mode synthesis is much shorter than that of whole structure analysis. The natural frequencies of lower modes obtained from component mode synthesis are almost same as those obtained from whole structure analysis, but in higher modes the differences between those two methods are increases. ii) The transfer function obtained from building block analysis is same as that obtained from the finite element method. iii) Same transfer functions can be obtained by the reduced impedance method. The computation time of reduced impedance mathod is shorter that that of general finite element method, but for the solutions in broad frequency band it requires long calculation time.

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Topology Optimization of Cylinder Block using Component Mode Synthesis (구분모드합성법을 이용한 실린더블록의 위상 최적 설계)

  • 윤성호;윤영근
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.3
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    • pp.177-183
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    • 2003
  • Vibration analysis using component mode synthesis method was carried out to identify that to some extent each component contributed to the whole vibration of a powertrain consisting of several components. This analysis helped decide the component to be modified to reduce the powertrain weight, without degrading its current vibration characteristics. As a result, a cylinder block was chosen as a redesign object. Topology optimization analysis was performed to design the topology of the cylinder block whose flange connected with the transmission was chosen to be the design domain. After all, a new prototype of cylinder block was manufactured based on the analysis results for the verification experiment. It was confirmed from the analytical and experimental results that u optimally designed cylinder block had an advantage over the current one in the powertrain weight, with the powertrain vibration characteristics improved slightly.

Comparison of Component Mode Synthesis and Substructure Synthesis Methods (구분모드합성법과 부분구조합성법의 비교)

  • Kwak, Moon-K.;Na, Sung-Soo;Bae, Byung-Chan
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.05a
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    • pp.1348-1353
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    • 2006
  • This paper is concerned with the comparison of component mode synthesis md substructure synthesis methods. Those two methods were developed for the dynamic analysis of complex structure. However, the difference between two methods in solving the dynamic problem has never been explained. In this paper, a structure consisting of two beams is considered for the application of two methods. The dynamic formulation shows the characteristics and differences of two methods. The procedure for choosing proper substructure modes in each method is explained in detail. In addition, the advantage of the substructure synthesis method is discussed based on the numerical example. Numerical examples show how two methods are applied to the addressed problem.

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Modal Parameter Sensitivity Analysis Using Component Mode Synthesis Method (부분 구조물의 모드 합성을 이용한 구조물 모드 매개변수의 민감도 해석)

  • 김형중;박윤식
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1997.04a
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    • pp.184-191
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    • 1997
  • A method, termed as the substructural sensitivity synthesis method, which utilizes the computational merits of the component mode synthesis technique is proposed to calculate design sensitivity of modal parameters of substructurally combined structures. In this method, the sensitivity analysis is combined with component mode synthesis thchnique. thus the degrees of freedom of a combined structure can be dramatically reduced. Free-interface mode method including the residual attachment modes among the component mode synthesis methods is used to calculate the modal sensitivity of the combined structure. For the design sensitivities of modal properties of structure, the Nelson's method, which is exact solving method is used. It is shown that the modal sensitivities of the entire structure can be obtained by synthesizing the substructural modal data, and the sensitivities of the modal data about the design variables of modifiable substructure. Using the proposed method, the final degrees of freedom of entire structure can be remarkably reduced to calculate the modal parameter sensitivities. With a structure composed of beams and plates, as an example, the sensitivities of the eigenvalues and eigenvectors obtained by this proposed method were compared with the exact solutions in terms of accuracy.

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Application of Substructure Synthesis Method for Analysis of Acoustic System (음향계의 해석을 위한 부분구조합성법의 적용)

  • 오재응;고상철;조용구
    • Journal of KSNVE
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    • v.7 no.5
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    • pp.737-746
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    • 1997
  • The substructure synthesis method is used for making it easy to analyze vibration systems generally in vibration field. In the past, this method has been to be used mainly because of shortage of computer memory and CPU time. But recently this method is used for analyzing complex structure or identifying the characteristics of systems precisely. The purpose of this study is to develop acoustic substructure synthesis method that can be applied to acoustic modal analysis of complex acoustic systems. Acoustic modal analysis method to be introduced here is a method that analyze acoustic natural mode shape of the complex acoustic system by the principle of CMS(component mode synthesis method). This paper describes the acoustic modal analysis of the acoustic finite element model of simple expansion pipe by acoustic substructure synthesis method. The resutls of acoustic modal analysis analyzed by Acoustic substructure synthesis method and the results by FEM(finite element method) shows good agreement.

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